1. Field
The present invention relates to a handheld device in which a plurality of side keys are provided for performing predetermined operations such as volume adjustment and particularly relates to a handheld device in which side keys are integratedly coupled with a film sheet such that the handheld device can be assembled without difficulty and in a downsized form.
2. Description of the Related Art
In a typical cellular phone, a movable-side housing with a display panel and a stationary-side housing with an operation panel are coupled in a foldable manner. In recent years, with the popularization of cellular phones having one-segment broadcast functionality, volume adjustment keys (side keys) used to adjust the volume of radio broadcast or television broadcast are attached to a lateral side of the stationary-side housing of a cellular phone (e.g., see Japanese Patent Application Laid-open No. 2005-252343). Such side keys on a lateral side of the stationary-side housing of a cellular phone are maintained coupled to the lateral side of the stationary-side housing with the use of, e.g., a rubber plate.
Given below is the description with reference to FIGS. 7A and 7B of a side-key attachment configuration in a conventional cellular phone. FIG. 7A is side view for explaining a pre-coupled condition of side keys and a rubber sheet. FIG. 7B is side view for explaining a coupled condition of side keys and a rubber sheet.
As shown in FIG. 7A, each of two side keys 40a includes a side key body 41, a bottom plate 43 located beneath the corresponding side key body 41 and an outwardly (toward downside in FIGS. 7A and 7B) protruding pin 44. A rubber sheet 70 is a long sheet-plate that has a circular hole 71 on each end of its body for inserting therethrough the pins 44 of the side keys 40a. 
As shown in FIG. 7B, the side keys 40a are fixedly attached to the rubber sheet 70 by applying an adhesive over a predetermined portion of the rubber sheet 70. In this way, the side keys 40a can be fabricated into an integrated key switch.
By operating the fixedly coupled side keys 40a, it is possible to switch ON or switch OFF an operation switch disposed on a circuit board (not shown) inside a stationary-side rear case 120. More particularly, e.g., it is possible to adjust the volume of broadcast by operating the pin 44.
In the case of the above-mentioned conventional side-key attachment configuration in a cellular phone, the independent side keys 40a are coupled with the rubber sheet 70. However, it consumes time to fabricate the rubber sheet 70 of predetermined dimensions. Moreover, it is also necessary to manufacture the rubber sheet 70 as a relatively thick sheet (thickness t of about 0.3 mm). Thus, a portion L1 at both ends of the fabricated rubber sheet 70 is surplus as compared to external dimension L of the side keys 40a. That condition stands in the way of manufacturing small and slim cellular phones.